1. Technical Field
The present invention relates to an electro-optical device driver circuit used for driving an electro-optical device such as a liquid crystal device, the electro-optical device that is provided with the electro-optical device driver circuit, and an electronic apparatus that is provided with the electro-optical device. An example of the electronic apparatus is a liquid crystal projector.
2. Related Art
In an electro-optical device, a plurality of data lines and a plurality of scanning lines are formed over a substrate as intersecting lines. A pixel including a pixel electrode is formed at a position corresponding to each of the intersections of the data lines and the scanning lines. The pixels are formed in a matrix pattern in a plan view. Each of the pixels includes a pixel-switching element. An example of the pixel-switching element is a thin film transistor (TFT). When the electro-optical device is driven, a scanning signal is supplied from a scanning line driving circuit to each pixel through a scanning line, thereby switching a pixel-switching element ON. When a pixel-switching element is in an ON state, an image signal is supplied to a pixel electrode from a data line via the pixel-switching element.
In such an electro-optical device, off sequence operation is carried out in order to avoid irregular residual charge at a plurality of pixels. The irregular residual charge is a phenomenon that occurs at the time of discontinuing display (when entering an OFF state), for example, when power supply is shut off (power OFF). In the off sequence operation, signals having the same predetermined voltage level (for example, image signal corresponding to black) are supplied to all of the plurality of pixels before power OFF (for example, refer to JP-A-2004-219682 and JP-A-2008-164843). With such off sequence operation, it is possible to practically even out residual charge that would otherwise remain irregularly at a plurality of pixels after power OFF depending on an image having been displayed in a pixel area immediately before the start of the off sequence operation. Therefore, it is possible to avoid an afterimage from being displayed in the pixel area (that is, the occurrence of a so-called “burn-in” phenomenon).
However, there is a technical problem in related art in that it could take long to perform off sequence operation described above (hereinafter referred to as “off sequence time”). For example, in a typical off sequence operation, a plurality of scanning signals is supplied from a scanning line driving circuit sequentially onto a plurality of scanning lines (which means the sequential scanning of the plurality of scanning lines) so as to put a plurality of pixel-switching elements each of which is formed in a pixel into an ON state and, in addition, signals having a predetermined voltage level are supplied onto a plurality of data lines. When off sequence operation is performed in such a way, it takes a comparatively long time to complete the sequential scanning of all of the plurality of scanning lines. This is the reason why there is a possibility that time required for off sequence operation is long. Especially, the larger the number of scanning lines, the longer the off sequence time.